SEL-751A Feeder Protection Relay

Making Electric Power Safer, More Reliable, and More Economical®

Industry-Leading Quality, Reliability, and Service

—40°C +85°C

Easily Mount in Existing Cutouts With Optional Mounting Kits

Substation-Hardened Ethernet

Arc-Flash Light Sensors

Arc-FlashOvercurrentFault

Current

ArcFlash

High-Speed Arc-Flash Detection Improves Safety

Choose the SEL-751A for feeder

overcurrent protection with

optional arc-flash detection.

SEL

Auto-Reclosing

Synchronism Check

Overcurrent

• Sequential Events Recorder

• Event Reports and Load Profiles

• SEL ASCII, Ethernet*, Modbus® TCP*, IEC 61850*, DNP3 LAN/WAN*, DNP3 Serial*, Modbus RTU, Telnet, FTP, and DeviceNet™ Communications*

• Event Messenger Compatible

• Front-Panel LED Programmable Targets

• Two Inputs and Three Outputs Standard

• I/O Expansion*—Additional Contact Inputs, Contact Outputs, Analog Inputs, Analog Outputs, and RTD Inputs

• ST® Fiber-Optic Communications Port*

• Single or Dual Ethernet, Copper or Fiber-Optic Communications Port*

• Battery-Backed Clock, IRIG-B Time-Synchronization

• Instantaneous Metering

• Programmable Front Pushbuttons and LED Indicators

• Advanced SELOGIC® Control Equations

• 32 Programmable Display Messages

• Station Battery Monitor*

• Breaker Wear Monitoring

• Synchrophasor Protocol

• Arc-Flash Protection*

• Peak Demand, Demand Metering*

• Aurora Mitigation Islanding Detection (81RF element)*

* Optional Functions

• Phase• Ground• Neg-Seq

• Phase• Ground (calculated or measured IG)• Neg-Seq

Time-Overcurrent

Arc-Flash NeutralOvercurrent

27

51N50N50NAF

50PAF 50 51

PGQ

PGQ

OvervoltageUndervoltage

Neutral Time-Overcurrent

NeutralOvercurrent

Undervoltage Overvoltage Frequency

AFD

Arc-FlashOvercurrent

Arc-Flash Detector

Power Elements

81 OUR

RF

32

59PGQ

27 59

79

25

52

Measured Residual Current IG*CBCT

Breaker

Line

• Single or dual, copper or fiber-optic Ethernet port(s)

• Modbus® TCP, DNP3 serial and DNP3 LAN/WAN, FTP, and Telnet protocols

• IEC 61850

• DeviceNet™

• EIA-232 or EIA-485 communications

• Fiber-optic serial port

• Additional EIA-232 or EIA-485 port

• Analog I/O—4 AI/4 AO, 8 AI

• Digital I/O—4 DI/4 DO, 4 DI/3 DO (2 Form C and 1 Form B), 8 DI, 3 DI/4 DO/1 AO

• Voltage options, including monitoring package inputs (three-phase voltage input, synchronism-check input, and station battery monitor input); measured residual current input; Aurora islanding detection (81RF element); advanced monitoring and protection; and four-channel, fiber-optic AFD inputs and protection

• 10 RTDs

• Conformal coating for chemically harsh and high-moisture environments

• Multishot reclosing

• Configurable labels

Feature Overview

Power supply options include: 110—250 Vdc, 110—230 Vac, 24—48 Vdc.

Optional copper or fiber-optic Ethernet, Modbus® TCP, DNP3, or IEC 61850.

Positions for optional I/O cards and voltage input card.

Optional arc-flash detection card and sensors.

Fiber-optic serial port option.

Large 2 x 16 character liquid crystal display.

Available with “Aurora” islanding detection (81RF element).

Use default messages, or program up to 32 custom display labels.

Use default pushbuttons, or program your own pushbutton actions and labels.

Front-panel LEDs can be programmed to indicate custom alarms.

User-configurable labels option.

Optional multishot reclosing.

!Clas

s I

Zone 2

Hazardous Location

APPROVED

Functional Overview Ordering Options

Communications Media• Ethernet 10/100BASE-T

• Ethernet 100BASE-FX

• Single or dual Ethernet ports

• EIA-232 serial

• EIA-485 serial

• Fiber-optic, serial multimode ST®

connectors

Communications Protocols• MIrrorED BItS communications

• IEC 61850

• Modbus RTU/TCP

• DNP3 serial, LAN/WAN

• DeviceNet

• Telnet

• FTP

• Synchrophasors (IEEE C37.118)

Flexible Communication

Reduce Arc-Flash Hazard

Field remote terminal.

Central control room.

Engineering access.

In addition to arc-flash detection, the SEL-751A provides several other methods to limit personnel exposure to arc-flash hazards. Reduce the danger of explosive arc-flash incidents by reducing the available fault current energy or removing personnel from the danger zone. Coordinate protection for faster clearing times, and stay outside the danger zone completely with wireless or remote communication.

Relay

MIRRORED BITS®

Communications

Relay

Flash Protection

Prohibited

Restricted

Limited

Coordinate ProtectionUse SEL MIrrorED BItS® communications to coordinate upstream protection if a fault occurs. Coordination and fast-bus trip schemes allow short delays (two or three cycles) for backup protection, reducing arc-flash energy.

Stay Outside the Danger ZoneUse Ethernet or serial communications to remotely obtain metering, event, and maintenance information from the relay. Optional delayed breaker tripping or closing via pushbuttons allows personnel to move to a safe distance.

Combined light-sensing technology with fast overcurrent protection provides high-speed arc-flash detection without false tripping.

Line

Arc-Flash Light Sensors(up to four)

Arc-FlashOvercurrent

FaultCurrent

ArcFlash

Bare-fiber sensors detect light from the arc flash over the entire length of the fiber loop. This type of sensor is used for large areas, such as busbars.

Easily mounted point sensors detect light from the arc flash in confined areas.

Mounting and Enclosure Options

No cutting or drilling is required when you use the optional mounting kits. Replacement of existing protection is quick and easy!

Pullman, Washington USATel: +1.509.332.1890 • Fax: +1.509.332.7990 • www.selinc.com • info@selinc.com

© 2007—2010 by Schweitzer Engineering Laboratories, Inc. PF00154 • 20101111

Phase current

Light intensity

Operate times as fast as 2 ms

Fault-clearing time

5.0 7.5Cycles

10.0

Easy to Set and Use

Use acSELErator QuickSet® SEL-5030 Software to Set, Monitor, and Control the SEL-751A

• Save engineering time while keeping flexibility. Communicate with the SEL-751A through any ASCII terminal, or use the acSELErator QuickSet graphical user interface.

• Develop settings offline with a menu-driven interface and completely documented help screens. Speed installation by copying existing settings files and modifying application-specific items.

• Simplify the setting procedure with rules-based architecture to automatically check interrelated settings. Out-of-range or conflicting settings are highlighted for correction.

Use acSELErator Software to Retrieve and Display Event Reports Recorded by the SEL-751A

• Display event report oscillograms. View each report as a plot of magnitude versus time.Select analog and digital points to build a custom display. Analyze arc-flash events using light intensity and phase current waveforms recorded during the arc fault.

• Display phase and symmetrical component phasors. Display the phasor view of electrical data to better understand asymmetrical three-phase faults. Build a custom plot using per-phase and symmetrical component sequence currents and voltages.

• Retrieve event reports using serial or Ethernet communications links.

Mount the SEL-751A into multiple locations using our complete line of mounting and enclosure options. Choose from panel-mount, rack-mount, wall-mount, indoor, or outdoor configurations.

Panel-Mounting KitsReplace existing feeder protection with the SEL-751A and the applicable mounting kit. These kits provide everything needed to replace many existing feeder relays with the SEL-751A.

19-Inch Rack Mounting KitsUse a 19-inch rack mounting kit to easily install the SEL-751A and other SEL-700 series relays into 19-inch racks. A variety of kits are available for one or two relays, or to mount a relay with an FT-1 test switch (not included).

Wall-Mounting, Indoor, and Outdoor Enclosure KitsUse one of the many option kits to install the SEL-751A and other SEL-700 series relays into a variety of configurations.

Visit www.selinc.com/mounting_selector to see the complete selection of mounting and enclosure kits.

SEL-751A Feeder Protection Relay